Hi.
Not sure if your switching Avid programs but if you are the solution I’ve found is to create a new project in your Avid. Give an identical name to the project being copied.Save. Open the old project and copy over only the bin files (.avb). Basically your transferring everything but the project settings.
By the way. A project doesn’t have to be in the Projects folder to open. So if you navigate to the original project and it still doesn’t open then you know its a compatibility issue.
Hope this helps.